1 /** @file 2 Implementation of synchronization functions. 3 4 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR> 5 This program and the accompanying materials 6 are licensed and made available under the terms and conditions of the BSD License 7 which accompanies this distribution. The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php. 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13 **/ 14 15 #include "BaseSynchronizationLibInternals.h" 16 17 /** 18 Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics. 19 **/ 20 21 void _ReadWriteBarrier (void); 22 #pragma intrinsic(_ReadWriteBarrier) 23 24 25 #define SPIN_LOCK_RELEASED ((UINTN) 1) 26 #define SPIN_LOCK_ACQUIRED ((UINTN) 2) 27 28 /** 29 Retrieves the architecture specific spin lock alignment requirements for 30 optimal spin lock performance. 31 32 This function retrieves the spin lock alignment requirements for optimal 33 performance on a given CPU architecture. The spin lock alignment is byte alignment. 34 It must be a power of two and is returned by this function. If there are no alignment 35 requirements, then 1 must be returned. The spin lock synchronization 36 functions must function correctly if the spin lock size and alignment values 37 returned by this function are not used at all. These values are hints to the 38 consumers of the spin lock synchronization functions to obtain optimal spin 39 lock performance. 40 41 @return The architecture specific spin lock alignment. 42 43 **/ 44 UINTN 45 EFIAPI 46 GetSpinLockProperties ( 47 VOID 48 ) 49 { 50 return InternalGetSpinLockProperties (); 51 } 52 53 /** 54 Initializes a spin lock to the released state and returns the spin lock. 55 56 This function initializes the spin lock specified by SpinLock to the released 57 state, and returns SpinLock. Optimal performance can be achieved by calling 58 GetSpinLockProperties() to determine the size and alignment requirements for 59 SpinLock. 60 61 If SpinLock is NULL, then ASSERT(). 62 63 @param SpinLock A pointer to the spin lock to initialize to the released 64 state. 65 66 @return SpinLock is in release state. 67 68 **/ 69 SPIN_LOCK * 70 EFIAPI 71 InitializeSpinLock ( 72 OUT SPIN_LOCK *SpinLock 73 ) 74 { 75 ASSERT (SpinLock != NULL); 76 77 _ReadWriteBarrier(); 78 *SpinLock = SPIN_LOCK_RELEASED; 79 _ReadWriteBarrier(); 80 81 return SpinLock; 82 } 83 84 /** 85 Waits until a spin lock can be placed in the acquired state. 86 87 This function checks the state of the spin lock specified by SpinLock. If 88 SpinLock is in the released state, then this function places SpinLock in the 89 acquired state and returns SpinLock. Otherwise, this function waits 90 indefinitely for the spin lock to be released, and then places it in the 91 acquired state and returns SpinLock. All state transitions of SpinLock must 92 be performed using MP safe mechanisms. 93 94 If SpinLock is NULL, then ASSERT(). 95 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). 96 If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in 97 PcdSpinLockTimeout microseconds, then ASSERT(). 98 99 @param SpinLock A pointer to the spin lock to place in the acquired state. 100 101 @return SpinLock acquired the lock. 102 103 **/ 104 SPIN_LOCK * 105 EFIAPI 106 AcquireSpinLock ( 107 IN OUT SPIN_LOCK *SpinLock 108 ) 109 { 110 UINT64 Current; 111 UINT64 Previous; 112 UINT64 Total; 113 UINT64 Start; 114 UINT64 End; 115 UINT64 Timeout; 116 INT64 Cycle; 117 INT64 Delta; 118 119 if (PcdGet32 (PcdSpinLockTimeout) == 0) { 120 while (!AcquireSpinLockOrFail (SpinLock)) { 121 CpuPause (); 122 } 123 } else if (!AcquireSpinLockOrFail (SpinLock)) { 124 // 125 // Get the current timer value 126 // 127 Current = GetPerformanceCounter(); 128 129 // 130 // Initialize local variables 131 // 132 Start = 0; 133 End = 0; 134 Total = 0; 135 136 // 137 // Retrieve the performance counter properties and compute the number of performance 138 // counter ticks required to reach the timeout 139 // 140 Timeout = DivU64x32 ( 141 MultU64x32 ( 142 GetPerformanceCounterProperties (&Start, &End), 143 PcdGet32 (PcdSpinLockTimeout) 144 ), 145 1000000 146 ); 147 Cycle = End - Start; 148 if (Cycle < 0) { 149 Cycle = -Cycle; 150 } 151 Cycle++; 152 153 while (!AcquireSpinLockOrFail (SpinLock)) { 154 CpuPause (); 155 Previous = Current; 156 Current = GetPerformanceCounter(); 157 Delta = (INT64) (Current - Previous); 158 if (Start > End) { 159 Delta = -Delta; 160 } 161 if (Delta < 0) { 162 Delta += Cycle; 163 } 164 Total += Delta; 165 ASSERT (Total < Timeout); 166 } 167 } 168 return SpinLock; 169 } 170 171 /** 172 Attempts to place a spin lock in the acquired state. 173 174 This function checks the state of the spin lock specified by SpinLock. If 175 SpinLock is in the released state, then this function places SpinLock in the 176 acquired state and returns TRUE. Otherwise, FALSE is returned. All state 177 transitions of SpinLock must be performed using MP safe mechanisms. 178 179 If SpinLock is NULL, then ASSERT(). 180 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). 181 182 @param SpinLock A pointer to the spin lock to place in the acquired state. 183 184 @retval TRUE SpinLock was placed in the acquired state. 185 @retval FALSE SpinLock could not be acquired. 186 187 **/ 188 BOOLEAN 189 EFIAPI 190 AcquireSpinLockOrFail ( 191 IN OUT SPIN_LOCK *SpinLock 192 ) 193 { 194 SPIN_LOCK LockValue; 195 VOID *Result; 196 197 ASSERT (SpinLock != NULL); 198 199 LockValue = *SpinLock; 200 ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED); 201 202 _ReadWriteBarrier (); 203 Result = InterlockedCompareExchangePointer ( 204 (VOID**)SpinLock, 205 (VOID*)SPIN_LOCK_RELEASED, 206 (VOID*)SPIN_LOCK_ACQUIRED 207 ); 208 209 _ReadWriteBarrier (); 210 return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED); 211 } 212 213 /** 214 Releases a spin lock. 215 216 This function places the spin lock specified by SpinLock in the release state 217 and returns SpinLock. 218 219 If SpinLock is NULL, then ASSERT(). 220 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). 221 222 @param SpinLock A pointer to the spin lock to release. 223 224 @return SpinLock released the lock. 225 226 **/ 227 SPIN_LOCK * 228 EFIAPI 229 ReleaseSpinLock ( 230 IN OUT SPIN_LOCK *SpinLock 231 ) 232 { 233 SPIN_LOCK LockValue; 234 235 ASSERT (SpinLock != NULL); 236 237 LockValue = *SpinLock; 238 ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED); 239 240 _ReadWriteBarrier (); 241 *SpinLock = SPIN_LOCK_RELEASED; 242 _ReadWriteBarrier (); 243 244 return SpinLock; 245 } 246 247 /** 248 Performs an atomic increment of an 32-bit unsigned integer. 249 250 Performs an atomic increment of the 32-bit unsigned integer specified by 251 Value and returns the incremented value. The increment operation must be 252 performed using MP safe mechanisms. The state of the return value is not 253 guaranteed to be MP safe. 254 255 If Value is NULL, then ASSERT(). 256 257 @param Value A pointer to the 32-bit value to increment. 258 259 @return The incremented value. 260 261 **/ 262 UINT32 263 EFIAPI 264 InterlockedIncrement ( 265 IN volatile UINT32 *Value 266 ) 267 { 268 ASSERT (Value != NULL); 269 return InternalSyncIncrement (Value); 270 } 271 272 /** 273 Performs an atomic decrement of an 32-bit unsigned integer. 274 275 Performs an atomic decrement of the 32-bit unsigned integer specified by 276 Value and returns the decremented value. The decrement operation must be 277 performed using MP safe mechanisms. The state of the return value is not 278 guaranteed to be MP safe. 279 280 If Value is NULL, then ASSERT(). 281 282 @param Value A pointer to the 32-bit value to decrement. 283 284 @return The decremented value. 285 286 **/ 287 UINT32 288 EFIAPI 289 InterlockedDecrement ( 290 IN volatile UINT32 *Value 291 ) 292 { 293 ASSERT (Value != NULL); 294 return InternalSyncDecrement (Value); 295 } 296 297 /** 298 Performs an atomic compare exchange operation on a 16-bit unsigned integer. 299 300 Performs an atomic compare exchange operation on the 16-bit unsigned integer 301 specified by Value. If Value is equal to CompareValue, then Value is set to 302 ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, 303 then Value is returned. The compare exchange operation must be performed using 304 MP safe mechanisms. 305 306 If Value is NULL, then ASSERT(). 307 308 @param Value A pointer to the 16-bit value for the compare exchange 309 operation. 310 @param CompareValue A 16-bit value used in a compare operation. 311 @param ExchangeValue A 16-bit value used in an exchange operation. 312 313 @return The original *Value before exchange. 314 315 **/ 316 UINT16 317 EFIAPI 318 InterlockedCompareExchange16 ( 319 IN OUT volatile UINT16 *Value, 320 IN UINT16 CompareValue, 321 IN UINT16 ExchangeValue 322 ) 323 { 324 ASSERT (Value != NULL); 325 return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue); 326 } 327 328 /** 329 Performs an atomic compare exchange operation on a 32-bit unsigned integer. 330 331 Performs an atomic compare exchange operation on the 32-bit unsigned integer 332 specified by Value. If Value is equal to CompareValue, then Value is set to 333 ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, 334 then Value is returned. The compare exchange operation must be performed using 335 MP safe mechanisms. 336 337 If Value is NULL, then ASSERT(). 338 339 @param Value A pointer to the 32-bit value for the compare exchange 340 operation. 341 @param CompareValue A 32-bit value used in a compare operation. 342 @param ExchangeValue A 32-bit value used in an exchange operation. 343 344 @return The original *Value before exchange. 345 346 **/ 347 UINT32 348 EFIAPI 349 InterlockedCompareExchange32 ( 350 IN OUT volatile UINT32 *Value, 351 IN UINT32 CompareValue, 352 IN UINT32 ExchangeValue 353 ) 354 { 355 ASSERT (Value != NULL); 356 return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue); 357 } 358 359 /** 360 Performs an atomic compare exchange operation on a 64-bit unsigned integer. 361 362 Performs an atomic compare exchange operation on the 64-bit unsigned integer specified 363 by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and 364 CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. 365 The compare exchange operation must be performed using MP safe mechanisms. 366 367 If Value is NULL, then ASSERT(). 368 369 @param Value A pointer to the 64-bit value for the compare exchange 370 operation. 371 @param CompareValue A 64-bit value used in a compare operation. 372 @param ExchangeValue A 64-bit value used in an exchange operation. 373 374 @return The original *Value before exchange. 375 376 **/ 377 UINT64 378 EFIAPI 379 InterlockedCompareExchange64 ( 380 IN OUT volatile UINT64 *Value, 381 IN UINT64 CompareValue, 382 IN UINT64 ExchangeValue 383 ) 384 { 385 ASSERT (Value != NULL); 386 return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue); 387 } 388 389 /** 390 Performs an atomic compare exchange operation on a pointer value. 391 392 Performs an atomic compare exchange operation on the pointer value specified 393 by Value. If Value is equal to CompareValue, then Value is set to 394 ExchangeValue and CompareValue is returned. If Value is not equal to 395 CompareValue, then Value is returned. The compare exchange operation must be 396 performed using MP safe mechanisms. 397 398 If Value is NULL, then ASSERT(). 399 400 @param Value A pointer to the pointer value for the compare exchange 401 operation. 402 @param CompareValue A pointer value used in a compare operation. 403 @param ExchangeValue A pointer value used in an exchange operation. 404 405 @return The original *Value before exchange. 406 **/ 407 VOID * 408 EFIAPI 409 InterlockedCompareExchangePointer ( 410 IN OUT VOID * volatile *Value, 411 IN VOID *CompareValue, 412 IN VOID *ExchangeValue 413 ) 414 { 415 UINT8 SizeOfValue; 416 417 SizeOfValue = (UINT8) sizeof (*Value); 418 419 switch (SizeOfValue) { 420 case sizeof (UINT32): 421 return (VOID*)(UINTN)InterlockedCompareExchange32 ( 422 (volatile UINT32*)Value, 423 (UINT32)(UINTN)CompareValue, 424 (UINT32)(UINTN)ExchangeValue 425 ); 426 case sizeof (UINT64): 427 return (VOID*)(UINTN)InterlockedCompareExchange64 ( 428 (volatile UINT64*)Value, 429 (UINT64)(UINTN)CompareValue, 430 (UINT64)(UINTN)ExchangeValue 431 ); 432 default: 433 ASSERT (FALSE); 434 return NULL; 435 } 436 } 437
